overview on past and present projects in germany to flight-test reentry … · overview on past and...

UniversitätStuttgart

INSTITUT FÜR RAUMFAHRTSYSTEMEwww.irs.uni-stuttgart.de

USERS Workshop, Tokyo, Oct. 8,2004

Overview on Past and Present Projects in Germany to Flight-Test Reentry Technologies

RLV HOPPER (EADS)

Ulrich M. Schöttle

USERS Workshop, Tokyo, Japan, October 8, 2004




OutlineH-2a

• Historical notes• Problems of reentry• Flight tests in 1990s • USERS project• Flight test projects (EU)

IRDT, EXPERTTETRA – SHEFEXASTRA / PHOENIX

• Concluding remarks




Historical Notes

• 1960: first successful recovery of reentry capsules• USA: 10.8.1960 Discoverer 13, UdSSR: 19.8.1960 Sputnik 5

• 1961: Vostok (Gagarin, first manned flight)• 1961-1972: Mercury, Gemini, Apollo (1st landing on moon 1969)• since 1967: Sojuz• since 1970 Planetary / asteroid missions: Venus (1970), Mars (1971),

Jupiter (1995), Saturn / Titan (2004); Muses-C, Rosetta

Winged Vehicles:• since 1981: Space Shuttle Orbiter (1988 Buran 1 flight)

Reentry Projects of J & EU:• 1994-1996: OREX, EXPRESS, HYFLEX (J)• 1995-1998: EXPRESS, MIRKA, ARD (EU)• 2003: USERS (operational s/c)




Why is Reentry Flight so Difficult to Achieve?

• Problem areas that must be mastered:– Rocket deorbit maneuver, AOCS – Thermal protection system (TPS) to withstand

extreme heating & mechanical loads – Aerothermodynamic prediction (AT CFD)– Navigation, guidance, and control (GNC)

of maneuvering lifting bodies in atmosphere– Blackout phenomena; landing & recovery ops.

→ Demand for flight testing– to demonstrate maturity of system concept

and / or technologies involved – Approach: ballistic – lifting – winged s/c

Columbia, Febr. 2003




Atmosphereh = 120 km

TAEM approach

Horizontal landing10000-14000km

Descent(exoatmosph.)

v = 7,6 km/s = 27360 km/hEntry

2000-4000km

Parachute landing

Ballistic

reentry

Short but highHeating rates

High deceleration(n = 6-20g)

GNCFlight control

Low, longHeating rates (10-20 min.)

Lifting flight

low deceleration< 2g

Ma ≈ 2,5h ≈ 24 km

Atmospheric Flight




Mission Scenario of USERS

Source: Ijichi, Wakasugi (IAF-97-U.1.03)




Flight Tests of Past Decade

EXPRESS 1995(D-J-R)

• Material• Instrumentation

MIRKA 1997 (D; SPA, Sensors)

ARD 1998 (EU)System demonstr. , operation

Material, GNC, AT




Ballistic Capsules for Flight Testing Reentry Technologies

EXPRESS:(1995)

MIRKA:(1997)

Cooperation Japan – Germanypartial success, uncontrolled entry

German experiments:- PYREX, RAFLEX

hot temperature sensors

- CETEX high temp.resistant C/SiC tile

Cooperation Germany – RussiaObjectices achieved- Qualification of selfsupporting

SPA-structure concept- Aerothermodyn.(AT) experiments- Generate AT flight data base




MIRKA Recovery 1997

Recovery in Kazakhstan

Capsule damage due tosevere surface winds!

d = 1m / m = 154kg




Early Objectives of USERS (1995)

Project implementation to take advantage of experiences from EXPRESS, SFU

Promote utilization of space environment by:- Operational and utilization advantages vs. ISS (JEM, COF), EURECA

- Payload delivery & retrieval independent from US Space Shuttle → operational authority

- Providing excellent microgravity level for long duration experiments

- Lower operating cost, shorter lead and turn around times of experiments, etc.

Strong interest of German space industry for long term cooperation with Japan- Continuation of successful cooperation in EXPRESS project- joint development of a demonstrator & an operational USERS

joint research, and mutual use of space system- Management methods „Cheaper, Faster, Better“ employing conventional technology,

commercial parts, standardization of interfaces etc.

USERS proposal of G industry not supported by DARA, that opted for X-38




Achievements of the USERS Project

Main objectives fully met:- Long duration material processing experiment (SMAP) conducted

- Deorbit, reentry, and recovery operations successfully accomplished- vehicle dynamics & loads as expected, TPS performed well (though

some damage observed, Inatani 2003, Matsuoka et al. IAC-03-V.3.04)

- landing in planned area indicates adequate performance of deorbit maneuver control, and capsule aerodynamic behaviour

- Design methods employing conventional methods (e.g. ballistic entry, blunted cone, ablative TPS), commercial parts, and standardization techniques demonstrated with good resultsCheaper, faster ?

Unmanned on-orbit experiment infrastructure comprising SEM and REM qualified to benefit future research programs

→ Very ambitious project, impressive results




USERS Results / Lessons LearnedSEM Orbit operations established:- Any shortcomings / deficiencies observed ?

Reentry flight results:

- Anomalies experienced ?:- Amplitudes of tumbling motion and n-loads within limits

- Capsule Aerodynamics / TPS performance as expected ?

Lessons learned:- Mission operation, entry flight and recovery successful- Qualification of selfsupporting ablative design concept,

strengthening structure required ?- AT prediction accuracy vs flight data ?- Improvements of deorbit to reduce recovery area / cost ?- Extensions for controlled semi-ballistic flight planned?




Concept Demonstrator Capsules IRDT, ARD

IDU 2

Equipment ContainerShock-absorber Forebody

IDU 1

Thermal Protection Blanket

ARD:(1998)

IRDT:(2000-2004)

Atmospheric Reentry DemonstratorLow L/D for aerodynamic maneuvering

Objectives achieved, guided entry- 4 CMC samples embedded in shield

2 FEI test samples on cone- Aerothermodynamic Measurements- GNC hard- & software flight tested→ Discrepancies predictions and data

Inflatable Reentry, Descent Techn.Objectices:- Qualify IRDT concept (origin:

Mars 96 s/c; adapted to Earth entry) - Two flight tests in 2000 & 2002

not successful; next flight 11. 04→ Tests using infrastructure of R




IRDT Concept (cooperation EU-G-R)

• Ballistic cone shaped s/c, m ≈ 100kg

• Two inflatable structures

• Payload retrieval from ISS proposed

• Reflight mission IRDT-2R ìn Nov. 2004 ?

3,7m




PARES Using IRDT – Missionprofile (courtesy EADS)




In-Flight Research on Real Gas Effects (EXPERT)

EXPERTEuropean Experimental Reentry Testbed

Objectives: validate aerothermodyn. CFD predictions to improve deficiencies wrt fligth data by accurate measurements of critical phenomena

EXPERT Capsule (ESA)

Blunt cone / flap configuration

- Flow transition and separation- Catalicity and oxidation- Real gas effects on shock wave

boundary layer interaction

Vehicle and Mission:- Vehicles of different m = 250–400 kg- Launched by Russian Volna rocket - Three flight tests planned beginning

in 2006




TETRA – Reentry Technologies for Future STS

Demonstrator X-38 (NASA) → CRVGerman and ESA support:- Delivery of essential hardware / software- Engineering expertise in design, AT- GNC algorithms- Major EU interest → flight testing

Germany developed & qualified:- Nose assembly (Tsp ≤ 1750°C)

C/SiC Nose Cap, CMC tiles, sensors- Body flaps and Health Monitoring system- Flexible External Insulation (FEI)→ Experience will benefit future projects

Project X-38 cancelled by NASA




Aerothermodynamic CFD Predictions (AT)

Much progress, but problems exist :- Discrepancies between flight measurements

and aerothermodyn. prediction results- Real gas effects, flow transition, flow

separation, inadequate models of finite rate chemistry (catalicity, oxidation)Flight testing for CFD validation

Oxidation effects on C/SiC-TPS:- Active oxidation results in significant

increase in temperature and surface erosion- Ref.-missions of X-38, EXPERT enter

passive-active transition regime- Adverse effects on reusability to be avoided




Sensorsystem PYREX-KAT38

Temperature distribution on Nose:- Heating rates max. at stagnation area

temperatures up to 1750°C

- PYREX measurement locations shown

Six channel sensor system: - Qualified for flight X-38 V201




Motivation for Facetted Design Concept SHEFEX

original facetted design

length:max. 0.8 m

⇒ reduced manufacturing cost by flat panels (∼70 %), and improved inspection, maintenance and repair expected




Objectives of SHEFEX Flight Experiment

SHEFEX goal:- Suborbital flights for concept testing

- Launch by two stage rocket system(DLR Moraba; VS 30, Orion)

Experimental vehicle:

- lenght ~1 m, diameter ∼ 0.5 m- Convex and concave shapes- Different TPS panels used;

CMC, metallic, FEI




SHEFEX Mission Profile

300

200

100

100 300 500

Höh

e [k

m]

Zeit [s]

Trennung Ogive90.0 km

Start RCS Manöver95.0 km

Brennschluss 2. Stufe65.5 km

Zündung 2. Stufe19.0 km

Trennung 1. Stufe17.5 km 20 km

90 km

300

200

100

100 300 500

Höh

e [k

m]

Zeit [s]

Trennung Ogive90.0 km

Start RCS Manöver95.0 km Start RCS Manöver95.0 km

Brennschluss 2. Stufe65.5 km

Zündung 2. Stufe19.0 km

Trennung 1. Stufe17.5 km 20 km

90 km

Altitude-velocity profile

(HEG High Enthalpy Tunnel))

Mission Profile- Second stage attached to provide control - Jettisoned before parachute deployment - Experiments in h ≈ 100 – 40 km, 20 – 30 s




ASTRA – PHOENIX Flight Experiment

ASTRA (D):Advanced Systems & Technologies for RLV Applications

launchat 40m/s

flare

125m/s

runway

diveRLVapproachpath -26o

2.4km

650m

3.2km6.9km

touch down73m/s

Free-flight profile

launchat 40m/s

flare

125m/s

runway


2.4km

650m

3.2km6.9km

touch down73m/s

Free-flight profile

launchat 40m/s

flare

125m/s

runway


2.4km

650m

3.2km6.9km

touch down73m/s

Free-flight profile

- Develop RLV technologies- Design representative test vehicle

PHOENIX (rear c.g.!)- Demonstrate GNC, automatic

landing capability

Flight tests:- Three flight tests successfully

performed in May 2004 at Vidsel / Sweden

Growth potential:- Structural design allows extension

of flight envelope to Ma ~ 2- 2.5

Future steps:- Propelled PHOENIX-2 (VTO,

HTO) within FLPP of ESACourtesy EADS




Concluding Remarks

• Overview given on EU reentry flight test programs (incomplete)with emphasis on German contributions

• Long term goals of German main efforts are winged RLV

• Broad EU flight test projects seem fragmented; many projects with different goals by various countries / organizations

• By comparison, the Japanese approach appears straight forward, steps:

EXPRESS / SFU → operational USERS

HYFLEX, ALFLEX, HSFD → reusable HOPE-X




ERNO EXPRESS Configuration

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